Microminiature multipole, multiposition, electrical switch construction



March 2, 1965 A. M. RUBIO ETAL 3,171,905

MICROMINIATURE MULTIPOLE, MULTIPOSITION, ELECTRICAL SWITCH CONSTRUCTION Filed Jan. 22, 1962 IIIIIIIII IIIIIIIIA ATTORNEYS.

United States Patent 3,171,965 MICROMlNIATURE MULTHPOLE, MULTIPOSI- TION, ELECTRIQAL SWITCH (IONSTRUCTIQN Alfred Martin Rubin, Chicago, and William G. Horier,

Wheeling, 111., assignors to Beitone Electronics Corporation, a corporation of Illinois Fiied Jan. 22, 1962, Ser. No. 167,679 3 Claims. (13!. 2130-11) This invention relates in general to microminiature switches, and more particularly to a new and improved multipole, multiposition switch of small dimension so as to be particularly suitable for use in electrical compact apparatus such as hearing aids or tape recorders or miniature radios or the like.

It is one object of the present invention to provide a new and improved microminiature, multipole multiposition switch such as may be used for selectively controlling a plurality of functions in different switch positions.

It is another object of the present invention to fabricate an improved microminiature, multipole, multiposition switch utilizing a relatively small number of inexpensive and reliable components.

Another object of the present invention is to provide a novel manually operable switch of very small dimensions for selecting any one of a plurality of different functions which does not require the visual monitoring of the switch operation.

. It is still another object of the present invention to provide an improved switch assembly for use with printed circuit contacts.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawings, in which:

FIG. 1 is a top plan view of an illustrative switch assembly embodying the invention;

. FIG. 2 is a side elevational View partly in cross-section of the illustrative switch assembly of FIG. 1;

FIG. 3 is a top elevation of the wiper knob forming a part of the illustrative switch assembly of FIG. 1;

FIG. 4 is a bottom elevational view of the wiper knob shown in FIG. 3 and particularly illustrating the wipers;

FIG. 5 is a sectional view taken through the line 5-5 in FIG. 1 for illustrating the manner in which a detent engages the wiper knob;

FIG. 6 is a sectional view taken along the line 66 in FIG. 1 and particularly illustrating the wiper assemy;

FIG. 7 is a top elevational view of an illustrative switch panel adapted for use in the assembly of FIG. 1;

FIG. 8 illustrates an alternative arrangement in which the wiper knob is arranged to also operate a lever or control a mechanical function; and

FIG. 9 is a sectional view taken through the line 99 in FIG. 8.

In the drawings, an illustrative switch assembly embodying the present invention is indicated by the reference character 11). Advantageously, the assembly is characterized by its relatively small number of parts and comprises a snap action detent bracket 12, a wiper knob 14, and a switch panel 16 mounted on a supporting structure 26.

The detent bracket 12 preferably may take the form of a generally elliptical-shaped sheet of stainless steel spring material and is provided with one straight edge, as at 18, parallel to the long axis of ellipse. A pair of bentover ears 20 and 22 are provided on the bracket 12 at opposite ends of the long axis and these are fastened to Patented Mar. 2, 1955 a supporting structure 26, as by means of screws 28 extending through suitable apertures in the switch panel 16. The top surface of the bracket 12 is generally flat; however, three equally spaced-apart detents or projections 30, 32 and 34 extend downwardly from the bottom surface of bracket 12. These detents are adapted to engage respective ones of a series of spaced-apart recesses 36 provided on the top surface of knob 14 and positioned adjacent the periphery thereof.

The knob 14 is generally circular in shape and is rotatably secured to switch panel 16 by a rivet shaft 38, as best seen in FIG. 2. The bracket 12 is adapted to overlie the knob 14, while a nylon washer 40, together with a tension washer 42 are provided on the shaft between a retaining member 44 and the underside of the knob 14 so as to bias the detents 3t), 32 and 34 into the respective recesses 36. Advantageously, the bracket 12 is provided with a suitably large opening adjacent the head of rivet shaft 38. This permits the use of an axial projection for the knob 14, as from the rivet shaft 38 to effect the desired rotation of knob 14.

In accordance with a feature of one embodiment of this invention, the knob 14 may be provided with a series of spaced-apart indentations 46 along its peripheral edge. The periphery of knob 14 protrudes beyond the straight edge 18 of the detent bracket 12 so that-the knob 14 may easily be rotated by the frictional movement of a finger or other operator thereagainst in lieu of rotation by an axial projection from the knob extending through the bracket openingv A stop element 511 is formed on the periphery of knob 14 and it too protrudes past the straight edge 16. The stop element 50 permits the knob 14 to be rotated in either direction until the stop abuts the supporting structure 26 which is provided with suitable upstanding or flange portions 51 to coact with the stop in limiting the range of rotation of the knob 14.

j A series of three, spaced-apart, rectangularly-shaped recesses 52, 54 and 56 are provided on the underside or lower surface of the knob 14. Advantageously, a stainless steel wiper assembly 58 is carried in each of these recesses. In one embodiment of this invention, as clearly seen in FIGURE 6, the wiper assemblies 58 each comprise a spring wiper element 61 and a retainer rivet 62. The wiper 60 comprises a pair of spaced-apart generally rectangular cross plates 64 and 66 integrally joined by a pair of elongated, folded-over legs 68 lying along respec tive longer and shorter chords of the knob 14. A pair of rounded contact projections 71 and 71 are formed at the center of respective legs 68 of each wiper so that the projection 71 lies on a short chord and the projection 71 on a longer chord.

The retainer rivet 62 may be formed of brass and with a head 72 at one end of its shank. The head 72 is adapted to be engaged against the top surface of the knob 14. At the other end of its shank, the rivet carries a rectangular member 74. The member 74 may be inserted between the plates 64 and 66 and when rotated to bring its long axis parallel to the legs 68, it is engaged across the plates 64 and 66 to positively retain the wiper 60 and prevent it from normally becoming disengaged from the knob 14.

The switch panel 16 comprises a flat insulating sheet 75, such as a printed circuit board, on which in one illustrative embodiment of the invention there are deposited three contact groups 76, 78 and 80, each having five conductive strips 81. Each group is associated with a respective one of the wipers 6h. The conductive strips 81 are arranged along the respective radial lines of circles concentric with the knob 14 and each strip terminates in a contact 82 underlying a, respective one of the contact projections 70 on the wipers. A common conductive segment, identified at 84, 86 and 88, respectively, also is dea posited on the sheet or printed circuit board 75 for each group of five strips 81.

In accordance with a feature of this invention, each of these common segments 84, Sound 88 operatively underlie a respective one of the contact projections '71 on the Wiper 60. External connections may be established to the respective conductive strips 81, contacts 82 and common segments 84, 86 and 88 by means of wires extended through suitableapertures 98* provided in the sheet or printed circuit board 7Sand also provided in both the conductive strips 81 and the common segments 84, 36 and 88.

in the operation of the invention, the knob 14 may simply be manually rotated from one position to another, usually as by frictionally moving a finger on the knob periphery. When manual pressure is applied to the knob 14, the detents 3t 32 and 34 arelifted from their corresponding recesses 36 against .the resilience of the spring bracket 12 as the knob rotates. Further rotative movement of the knob 14 then is comparatively free until the detents 30, 32 and 34 engage or snap into the next series of recesses 36. This positively locates the switch positions and further movement is terminated unless additional rotative pressure is applied. By virtue of this snap action, the operator of course immediately knows that the switchis in the proper new switch position without visual inspec-.

tion.

The contact projection of one leg 68 of each of the wipers 60 is operatively associated for sliding contact with a respective common segment while the contact projection on the other leg 68 is associated for sliding contact with one of the contacts 82 of a respective contact group 76, 78, or Thus, an electrical connection is established from each common segment by means of a contact projection 71 on one wiper leg through the contact projection 7d on the other wiper leg to any one of the five conductive, strips 81 in its associated contact group. With this arrangement a number of diiferent switching functions maybe selected. Thus, in a tape recorder, the

knob 14 may complete circuits for controlling the motoroperation, clutch operation and record or playback operations, for example, with the control function being varied in accordance with the position of knob 14. Or in a hearing aid, for example, one contact group may control operation of the power supply function, another contact group may control operation of tone control and telephone coil functions, while a third contact group, if desired, may control a power level function. Many other uses of the multipole, multiposition switch of the present invention, such as in a miniature radio and the like, will occur to those skilled in the art. Further, it will be appreciated that the invention may be used in an arrange-' ment wherein a plurality of printed circuit boards or panels are stacked so as to provide a gauged wafer switch of extremely small dimension and of increased circuit handling capabilities.

The three spaced detents 30, 32 and 34 insure that contact pressure is applied equally to all of the wipers. The stop 50 insures that the knob is not rotated beyond a predetermined limit so that each wiper is always associated with its own contact group, and further to permit the switchposition to be determined by feel as well as by sight.

In accordance with a further feature of this invention, the microminiature switch may be adapted to actuate a mechanical assembly. In the illustrative arrangement shown in FIG. 8, several cam surfaces 91 and 92 are shown on the knob 14. The cam surfaces are arranged to coact with a lever 94 along a portion of the inner periphery of knob 14 upon which the recesses 46 may be omitted. The lever 94 advantageously is pivoted at 96 and a spring 98 serves to bias the lever 94 against the periphery of the knob 14. Therefore, as the knob 14 is rotated, the lever 94 is held in engagement therewith so 41. that it may be operated or actuated by the cam surfaces 91 and 92. Thus the knob 14 may also provide mechanical functions which are useful in appliances such as tape recorders and the like.

Since the components, such as the lever and knob, are of extremely small dimension, it is desirable to insure that they are held in proper alignment. Towards this end, the knob 14 may be provided with a concave surface and the lever 94 with a convex surface 102. so that they positively engage each other when the knob is rotated.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim as new, and desire to secure by Letters Patent of the United States, is:

1. A microminiature switch construction comprising a spring plate having a plurality of spaced-apart detents formed in one surface and depending therefrom, a knob,

' fastening means rotatably suspending said knob below said one surface of said spring plate and having a plurality of spaced-apart recesses in one side thereof, means biasing said depending detents into engagement with said knob whereby said recesses are each engaged in sequence with a respective one of said detents upon rotation of said knob for properly locating said knob in any one of a plurality of positions, said biasing means comprising a spring washer mounted upon said fastening means at the other side of said knob and equidistant from said detents, a plurality of contact elements positioned within the switch and facing the other side of said knob, and a spring wiper carried on the other side of said knob for sequential en gagement with each of saidcontact elements upon rotation of said knob.

2. A microminiature switch construction comprising a spring plate having a plurality of spaced-apart detents thereon, a knob, fastening means rotatably suspending said knob from said spring plate, mating means on said knob shaped to receive said detents for operatively holding said knob in any one of a plurality of switch positions upon selective rotation of said knob, a support member having positioned thereon a plurality of groups of contacts together with a common contact for each group of contacts and a plurality of spring wipers carried on said knob equal in number to said groups of contacts, with each wiper serving to establish a closed electrical circuit from a respective one of said common contacts to selected ones of the contacts in each associated contact group upon rotation of said knob into its different switch positions.

3. A microminiature switch construction in accordance with claim 2 in which said knob comprises a thin disc having an arcuate cam edge along one portion of its periphery, a pivoted lever positioned for engagement with the camedge of said disc, and an edge on said lever having an arcuate configuration complementary to said one arcu-ate cam edge to prevent transverse disengagement between the disc and the lever during rotation of said knob.

References Cited by the Examiner UNITED STATES PATENTS 1,598,666 9/26 Voorhees. 2,854,564 9/58 Gahagan 200l1 2,965,913 12/60 Ziegler 20011 3,072,756 1/63 Koci ZOO-11 FOREIGN PATENTS 56,702 7/44 Holland.

BERNARD A. GILHEANY, Primary Examiner,

Ma num, 

1. A MICROMINIATURE SWITCH CONSTRUCTION COMPRISING A SPRING PLATE HAVING A PLURALITY OF SPACED-APART DETENTS FORMED IN ONE SURFACE AND DEPENDING THEREFROM, A KNOB, FASTENING MEANS ROTATABLY SUSPENDING SAID KNOB BELOW SAID ONE SURFACE OF SAID SPRING PLATE AND HAVING A PLURALITY OF SPACED-APART RECESSES IN ONE SIDE THEREOF, MEANS BIASING SAID DEPENDING DETENTS INTO ENGAGEMENT WITH SAID KNOB WHEREBY SAID RECESSES ARE EACH ENGAGED IN SEQUENCE WITH A RESPECTIVE ONE OF SAID DETENTS UPON ROTATION OF SAID KNOB FOR PROPERLY LOCATING SAID KNOB IN ANY ONE OF A PLURALITY OF POSITIONS, SAID BIASING MEANS COMPRISING A SPRING WASHER MOUNTED UPON SAID FASTENING MEANS AT THE OTHER SIDE OF SAID KNOB AND EQUIDISTANT FROM SAID DETESTS, A PLURALITY OF CONTACT ELEMENTS POSITIONED WITHIN THE SWITCH AND FACING THE OTHER SIDE OF SAID KNOB, AND A SPRING WIPER CARRIER ON THE OTHER SIDE OF SAID KNOB FOR SEQUENTIAL ENGAEMENT WITH EACH OF SAID CONTACT ELEMENTS UPON ROTATION OF SAID KNOB. 